Microcentrifuge tubes are small plastic tubes which are usually tapered, conical or rounded, and closed at one end. The tubes are capable of holding approximately 0.4-2.0 ml of liquid, and can withstand forces over 10,000×g during centrifugation. These tubes are used widely in biotechnology laboratories as vessels for storing chemical and biological reagents, for performing biochemical reactions, and for handling sterile contaminant-free samples. They usually have tight-fitting lids whose size and shape protect and cover the perimeter of the tube opening and help maintain the inside of the tube in aseptic condition.
The lids are generally attached to the tubes by a flexible hinge and are sealed to the tube by pressing them downward against a resisting frictional force. In this sealing process, the annular sealing portion of the underside of the lid, shaped to a sealing fit inside the tube opening, is forced downward into the tube and compressed. The lids are secured against accidental opening by a number of means such as friction force-fit of the lid in the tube, integrated lid “catches” which secure the lid to a lip flange provided on the tube, or alternatively by separate lid clamps which may be slid or snapped into place after the lid has been closed. For subsequently aiding in unseating and opening the sealed and optionally secured lid, the generally flat lid opposite the lid hinge is usually extended horizontally beyond the outer diameter of the tube's lip flange to provide a standard lifting tab. A thumb, thumbnail, or opener device may be used to press upward on this tab.
Microcentrifuge tubes are commonly used for clinical testing, wherein a test sample must be analyzed alongside a control sample to reach a conclusive result. In such applications, it is highly desirable that the control sample and the test sample be subjected to virtually identical mechanical and thermal treatments. This can be accomplished by providing an array or assembly of two or more microcentrifuge tubes attached to each other. Various examples of such arrays and assemblies have been described in the prior art; see, for example, U.S. Pat. Nos. D309,779; D316,449; 4,671,939; 5,005,721; 5,282,543; 5,683,659; 5,722,553; 6,001,310; 6,601,725; and U.S. Pub. No. 2007/0017927. However, there remains a need for improved microcentrifuge tube arrays that are robust, easy to handle, and inexpensive to manufacture. The present invention addresses this need.